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regulator: Add support for ramp delay

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Changing voltage and enabling regulator might require delays so the
regulator stabilizes at expected level.

Add support for "regulator-ramp-delay" binding which can introduce
required time to both enabling the regulator and to changing the
voltage.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
This commit is contained in:
Krzysztof Kozlowski 2019-03-06 19:37:54 +01:00 committed by Minkyu Kang
parent fce8610060
commit e66d1cb3c2
3 changed files with 49 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
doc/device-tree-bindings/regulator/regulator.txt
View File

@ -35,6 +35,7 @@ Optional properties:
- regulator-max-microamp: a maximum allowed Current value
- regulator-always-on: regulator should never be disabled
- regulator-boot-on: enabled by bootloader/firmware
- regulator-ramp-delay: ramp delay for regulator (in uV/us)
Note
The "regulator-name" constraint is used for setting the device's uclass
@ -60,4 +61,5 @@ ldo0 {
regulator-max-microamp = <100000>;
regulator-always-on;
regulator-boot-on;
regulator-ramp-delay = <12000>;
};

47
drivers/power/regulator/regulator-uclass.c
View File

@ -35,10 +35,22 @@ int regulator_get_value(struct udevice *dev)
return ops->get_value(dev);
}
static void regulator_set_value_ramp_delay(struct udevice *dev, int old_uV,
int new_uV, unsigned int ramp_delay)
{
int delay = DIV_ROUND_UP(abs(new_uV - old_uV), ramp_delay);
debug("regulator %s: delay %u us (%d uV -> %d uV)\n", dev->name, delay,
old_uV, new_uV);
udelay(delay);
}
int regulator_set_value(struct udevice *dev, int uV)
{
const struct dm_regulator_ops *ops = dev_get_driver_ops(dev);
struct dm_regulator_uclass_platdata *uc_pdata;
int ret, old_uV = uV, is_enabled = 0;
uc_pdata = dev_get_uclass_platdata(dev);
if (uc_pdata->min_uV != -ENODATA && uV < uc_pdata->min_uV)
@ -49,7 +61,20 @@ int regulator_set_value(struct udevice *dev, int uV)
if (!ops || !ops->set_value)
return -ENOSYS;
return ops->set_value(dev, uV);
if (uc_pdata->ramp_delay) {
is_enabled = regulator_get_enable(dev);
old_uV = regulator_get_value(dev);
}
ret = ops->set_value(dev, uV);
if (!ret) {
if (uc_pdata->ramp_delay && old_uV > 0 && is_enabled)
regulator_set_value_ramp_delay(dev, old_uV, uV,
uc_pdata->ramp_delay);
}
return ret;
}
/*
@ -107,6 +132,7 @@ int regulator_set_enable(struct udevice *dev, bool enable)
{
const struct dm_regulator_ops *ops = dev_get_driver_ops(dev);
struct dm_regulator_uclass_platdata *uc_pdata;
int ret, old_enable = 0;
if (!ops || !ops->set_enable)
return -ENOSYS;
@ -115,7 +141,22 @@ int regulator_set_enable(struct udevice *dev, bool enable)
if (!enable && uc_pdata->always_on)
return -EACCES;
return ops->set_enable(dev, enable);
if (uc_pdata->ramp_delay)
old_enable = regulator_get_enable(dev);
ret = ops->set_enable(dev, enable);
if (!ret) {
if (uc_pdata->ramp_delay && !old_enable && enable) {
int uV = regulator_get_value(dev);
if (uV > 0) {
regulator_set_value_ramp_delay(dev, 0, uV,
uc_pdata->ramp_delay);
}
}
}
return ret;
}
int regulator_set_enable_if_allowed(struct udevice *dev, bool enable)
@ -335,6 +376,8 @@ static int regulator_pre_probe(struct udevice *dev)
-ENODATA);
uc_pdata->always_on = dev_read_bool(dev, "regulator-always-on");
uc_pdata->boot_on = dev_read_bool(dev, "regulator-boot-on");
uc_pdata->ramp_delay = dev_read_u32_default(dev, "regulator-ramp-delay",
0);
/* Those values are optional (-ENODATA if unset) */
if ((uc_pdata->min_uV != -ENODATA) &&

2
include/power/regulator.h
View File

@ -150,6 +150,7 @@ enum regulator_flag {
* @always_on* - bool type, true or false
* @boot_on* - bool type, true or false
* TODO(sjg@chromium.org): Consider putting the above two into @flags
* @ramp_delay - Time to settle down after voltage change (unit: uV/us)
* @flags: - flags value (see REGULATOR_FLAG_...)
* @name** - fdt regulator name - should be taken from the device tree
* ctrl_reg: - Control register offset used to enable/disable regulator
@ -169,6 +170,7 @@ struct dm_regulator_uclass_platdata {
int max_uV;
int min_uA;
int max_uA;
unsigned int ramp_delay;
bool always_on;
bool boot_on;
const char *name;